This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Ypk1, is a well conserved protein kinase involved in endocytosis and cell growth. Interestingly, Ypk1 is highly phosphorylated in vivo. So far, three protein kinases have been identified as upstream regulators of Ypk1. However, the phosphorylated sites of this protein have not been examined in vivo. Furthermore, the downstream substrates of Ypk1 have not been identified. Recently I was able to purify Ypk1 using a TEV-myc-tagged system in yeast. Mass spec analysis of purified Ypk1p may identify Ypk1?s potential binding partners (substrates) and also phosphorylated sites of Ypk1.